Process of making copper powder



'atented June 15, 1937 UNITED hsrATE Proc ss. or MAKING oomarowmm Raymond I.

'Lutz, on Park,

111.. assignor to Western Electric Company, IncorporatetL'New I Zorlr, N. Y., a corporation of New York No Drawing. Application January 3 No. 96

- '12 Claims.

This invention relates to a process of, making.

An object of the present invention is to provide an effective and eflicient process of making cop per powder.

i In accordance with one embodiment of the invention the copper. powder containing sludge from a copper wire drawing machine is treated with a non-corrosive solvent to liberate the copper particles after which the particles are separated from the solution preferably by means of a centrifugal filter.

In the drawing of a copper wire it is customary to use a wire drawing compound comprising fat and soap dispersed in water to lubricate the dies 5 and capstan of the machine. During the drawing operation fine particles of copper are abraded from! the wire and these particles together with some of the spent drawing compound settle to the bottom of the machine and form a sludge.

lO'HGICtOfOI'B this sludge was either discarded or subjected to a burning and melting treatment from which the copper was recovered in the form [v of cast bars.

The recovery of the copper in powder form l5 from the sludge presents numerous difllculties. Some solvents for the sludge attack the copper and corrode it while others form slimes which prevent satisfactory separation of the copper powder. A satisfactory .solvent must have a'slight affinity for water since the sludge contains a small amount of water. It must also be a solvent for fats and copper soapswhich are present in the sludge. The copper soaps unless dissolved form 5 a slime from which it is impractical to separate the copper powder. The solvents which possess the necessary properties for, this process are chlorinated hydrocarbons such as ethylene di- 30 chlorethyl ether, or

chloride or trichlorethylene, ethers such as diketones such as diethyl ketone or methyl propyl ketone. If the solvent is filtered off the copper powder in such a manner as to leave the powder moist as for instance in a filter press it must be dried in a heated I non-oxidizing atmosphere as an inert s; a

fine or' impalpable 1, icsasemi as a hydrogen atmosphere at a temperature of approximately 500 F. to .obtain anon-oxidized copper powder. To avoid the use of such an atmosphere, it is preferable to use a centrifugal filter by means of which the solvent may be removed and the copper powder dried without material oxidation.

In practising the sludge from a wire drawing machine is mixed with a quantity of the solvent and the mixture is thoroughly agitated. While continuing the agitation the mixture is supplied through a suitable conduit to a centrifugal separator which retains the copper powder and expels the solvent. When a suitable amount of copper dust has accumulated in the centrifuge the supply of the mixture is interrupted and a small amount of cleansolvent is introduced into the copper powder of any remaining impurities. The powder is then dried in the centrifuge. In this mannerthe copper powder is dried by centrifugal force without any appreciable aeration of the powder which. would rapidly oxidize the fine powder.

It will be understood that the nature and embodiments of the invention herein described are merely illustrative and that manychanges and invention a quantity of the the centrifuge to wash vacuumor in a heated reducing atmosphere such modifications may be made therein without departing from the spirit and scope of the invention. what is claimed is:

1. A method of producing copper powder-which comprises drawinga copper wire with a fat and soap drawing compound whereby a copper containing sludge is formed, treating the sludge with anon-corrosive solvent which will not form a slime, and filtering the copper powder front the solution.

2. A method of producing copper powder which comprises drawing'a copper wire with a lubricating drawing compound whereby a copper containing sludge is formed, treating the sludgewith a non-corrosive solvent which will not form aslime, and filtering solution.

3. A method of producing copper powder which comprises drawing a copper wire with alubrithe copper powder from the cating drawing compound whereby a copper con-' taining sludge is formed, treating the sludge with a chlorinated hydrocarbon to dissolve the drawing compound and copper soaps, and separating the copper powder from the solution.

4. A method of producing copper powder which comprises treating the sludge from a copper wire the soluble constituents, and separating the copper powder byfilterlng the solution.

6. A method of producing copper powder which 10 comprises treating the sludge from a copper wire drawing machine with a solvent for the fluid constituents and copper soaps, and separating the copper powder from the solution by a centrii'ugal filter.

15 7. A method of producing copperpowder which comprises treating the sludge from a copper wire drawing machine with a. solvent for the fluid constituents and copper soaps. and and drying the copperpowder by a centrifugal A "12; A methodo! producing m use" 20 filter.

8. A method of producing'copper powderwhich? comprises mixing the sludge from a copper wire drawing machine with a solvent for the fluid constituents and copper soaps, supplying the 25 mixture to a centrifugal filter, interrupting the supply of the mixture and supplying clean solvent to the copper powder, and drying the copper powder by centrifugal force,

copper powder solution.

solution. g M g -1o.s 'method; o! g which comprises e sludge containing copperpowdeniatsndcoppersoepswithasol ventselected rromthegmupoi'achiorinatedhylo drocarbon, s chlorinecsd 'e'ther, or a ketone to dissolve the soluble consti ii. A method which comprises treatim a sludge containing his copper powder, water, fat, and copper soaps with a chlorinated ether to dissolve the soluble conts sndflltering the 'stituents and filtering the copper powder from the solution;

which comprises treating s. sludge copper powder,"water, rat and copper 'soeps'wim. r

a ketone to dissolve the soluble constitucntsand fiitering'the copper powder irom the solutionk i asmcnnr, 

